Second harmonic generation due to the effect of two different spin states of electron on the propagation of a circularly polarized laser pulse in homogenous high density quantum plasma is studied using the quantum hydrodynamic (QHD) model. The effects associated with the Fermi pressure, the Bohm-potential and the electron spin-up and spin-down have been taken in to account. The efficiency of the Second harmonic radiation is derived and the effect of spin polarization on the conversion efficiency has been analyzed.